JP2008195074A - Polymer resin film and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer resin film which does not generate coating unevenness when various types of functional layers are coated on the film surface in a transparent film for optical use, a film for supporting photographic material, and the like manufactured by the solution casting method, and a method of manufacturing the same. <P>SOLUTION: The polymer resin film manufactured by the solution casting method is characterized in that the pitch a [cm] of periodic thickness unevenness in the web longitudinal direction and the thickness unevenness factor d satisfy the following formula (1). The formula (1) is represented by d≤0.46a<SP>3</SP>-0.91a<SP>2</SP>+0.60a+1.01, where a is within the range of 0.2<a<3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transparent film for optical use such as a protective film for polarizing plate, a polymer resin film that can be used for a support film for photographic light-sensitive materials and the like, and more specifically, a functional layer is applied to the film surface. The present invention relates to a polymer resin film in which coating unevenness is prevented from occurring and a method for producing the same.

  In general, a cellulose triacetate film or the like is used as a film such as a transparent film for optical use or a support film for a photographic material, and the cellulose triacetate film or the like is manufactured by a solution casting method. In the solution casting method, a polymer solution dissolved in an organic solvent is cast from a die onto a support, and at the same time a casting ribbon (a liquid film between the die discharge port and the support landing) is provided by a decompression chamber provided near the die. The same applies hereinafter) to the support. As such a solution casting method, for example, in Japanese Examined Patent Publication No. 49-36946, a vacuum chamber having two suction chambers is provided in order to prevent air entrainment, and the liquid composition stream and the roller are brought into close contact with each other. A method of casting a liquid composition has been proposed. In Japanese Patent Publication No. 62-38133 and Japanese Patent Publication No. 63-57222, a web of a web that can stabilize an end bead by providing two vacuum zones with an isolation wall. A uniform pressing device has been proposed. In Japanese Patent Laid-Open No. 5-86212, etc., there is proposed a casting method that prevents the occurrence of burrs by using a dope having a specific ratio of a good solvent and a poor solvent. Yes.

  However, the polymer resin film manufactured by the above-described conventional solution casting method includes the air column vibration inside the decompression chamber, the air column vibration of the suction duct for decompression, the vibration of the decompression chamber transmitted by the blower vibration, etc. The casting ribbon vibrates at a certain frequency due to vibration disturbance due to wind pressure vibration or mechanical vibration, and minute periodic stepwise thickness unevenness occurs in the longitudinal direction of the film.

  In particular, in recent years, thinning of liquid crystal display devices (hereinafter referred to as LCDs) has progressed, and each element has been required to be thin, and the protective film for polarizing plates has been required to be thin. As a result, the leveling effect, which is a feature of the solution casting method, is reduced, and various thickness irregularities become apparent.

  By the way, the transparent film for optical use is coated with an anti-glare layer, for example, to give a hard coat or an antireflection function. Since it hinders the appearance value and functionality of the film, it has been a major quality problem in LCDs and the like.

  In addition, similar problems occur in emulsion coating in the photographic light-sensitive material support.

  The present invention solves the above problems and provides a polymer resin film in which coating unevenness does not occur even when various functional layers are applied to a film produced by a solution casting method and a method for producing the same. Objective.

  The present inventor has intensively studied to achieve the above object, and in a predetermined range of periodic longitudinal thickness unevenness, when the relationship between the thickness unevenness pitch and the thickness unevenness is in a predetermined region, the polymer resin It has been found that good appearance quality can be obtained even when a film is subjected to coating, and the present invention has been completed.

That is, the polymer resin film according to the present invention is formed by a solution casting method, and has a periodic thickness unevenness pitch a [cm] and a thickness unevenness rate d [%] in the longitudinal direction of the web. It is characterized by satisfying the following formula (1).
d ≦ 0.46a ³ −0.91a ² + 0.60a + 1.01 (1)
(However, 0.2 <a <3)

  Furthermore, the present inventor obtains good appearance quality even when the polymer resin film is subjected to coating, when the relationship between the stretch rate of the casting ribbon, the casting speed and the stretching frequency is in a predetermined region. And the present invention has been completed.

That is, the method for producing a polymer resin film according to the present invention is a method for producing a film by casting a solution in which a polymer resin is dissolved in an organic solvent from a die to a support, and a casting speed v [cm / s]. The expansion / contraction frequency f [1 / s] and the expansion / contraction rate e [%] satisfy the following expression (3).
e ≦ 0.46 (v / f) ³ −0.91 (v / f) ² +0.60 (v / f) +1.01
...... (3)
(However, 0.2 <(v / f) <3)

  The present invention sets the relationship between the pitch and the thickness unevenness in an appropriate region with respect to the periodic thickness unevenness generated in the longitudinal direction of the film manufactured by the solution casting method. Good appearance quality can be obtained even if the coating is used for coating.

In the polymer resin film of the present invention, the thickness unevenness pitch a and the thickness unevenness ratio d [%] are related to the stepwise thickness unevenness in which the thickness unevenness pitch a [cm] in the longitudinal direction of the web is in the range of 0.2 to 3 cm. Satisfies the following formula (1):
d ≦ 0.46a ³ −0.91a ² + 0.60a + 1.01 (1)
Furthermore, it preferably satisfies the following formula (2).
d ≦ 0.19a ³ −0.38a ² + 0.25a + 0.42 (2)

  That is, the inventor has shown in FIG. 1 the relationship between the pitch a [cm] of the periodic thickness unevenness in the longitudinal direction of the web and the thickness unevenness rate d [%] and the strength of the appearance of the coating unevenness. Results as shown were obtained. In FIG. 1, the curve a represents the above formula (1), the curve b represents the above formula (2), and the region above the curve a is a region where uneven coating appears strong, and the curves a and b The area between is an area where the coating unevenness appears weak, and the area under the curve b is an area where the coating unevenness is not visible. The intensity of such coating unevenness was determined by visual observation.

  The thickness unevenness ratio is a value obtained by dividing the difference between the maximum value and the minimum value of unevenness of thickness unevenness by the average thickness of the film. The measurement of the thickness unevenness pitch and the thickness unevenness ratio is a method of continuously measuring the thickness of the film in the longitudinal direction, and reading the periodic thickness unevenness pitch and the thickness unevenness maximum, minimum and average values from the chart, This can be done by frequency analysis of thickness variation values and a method of reading the maximum peak value. The continuous thickness measuring method can be performed by a contact-type continuous thickness meter, a non-contact type continuous thickness meter, or the like.

  In order to set the thickness unevenness pitch and thickness unevenness to the predetermined ranges as described above, the solution flow rate pulsation, the mechanical vibration of the casting part, the speed unevenness of the support, the static pressure fluctuation and the dynamic pressure fluctuation of the die lip discharge ribbon part This can be achieved by suppressing the amount of ribbon and setting an appropriate ribbon length.

  Moreover, when the pitch of thickness unevenness in the longitudinal direction of the web is 0.2 cm or less, the thickness unevenness rate is preferably 2% or less, and more preferably 1% or less. If the thickness unevenness ratio exceeds 2%, coating unevenness will appear strong.

  Furthermore, when the pitch of the thickness unevenness in the longitudinal direction of the web is 3 cm or more, the thickness unevenness ratio is preferably 7% or less, and more preferably 2.8% or less. If the thickness unevenness ratio exceeds 7%, the coating unevenness will appear strong.

In the method for producing the polymer resin film of the present invention, the casting speed v [cm / s] and the stretching frequency f [1 / s are obtained when the casting speed divided by the stretching frequency is in the range of 0.2 to 3 cm. ] And the expansion ratio e [%] of the casting ribbon satisfy the following formula (3):
e ≦ 0.46 (v / f) ³ −0.91 (v / f) ² +0.60 (v / f) +1.01
...... (3)
Furthermore, it preferably satisfies the following formula (4).
e ≦ 0.19 (v / f) ³ −0.38 (v / f) ² +0.25 (v / f) +0.42
...... (4)

  That is, the present inventor obtained the results as shown in FIG. 2 for the expansion ratio e, the casting speed v, and the expansion frequency f of the casting ribbon. In FIG. 2, the curve c represents the above equation (3), the curve d represents the above equation (4), and the region above the curve c is a region where coating unevenness appears strong, and the curve c, the curve d, The area between is an area where the coating unevenness appears weak, and the area under the curve d is an area where the coating unevenness is not visible. The intensity of such coating unevenness was determined by visual observation.

  The average length l of the casting ribbon is the length of the liquid film from the casting die discharge port to the support landing. The average length l of the casting ribbon is obtained from the average value obtained by taking a video of the casting ribbon and measuring the maximum length and the minimum length.

  The casting speed v is the moving speed of the support. The rotation speed of the support driving motor or the moving speed of the support is directly measured by a contact or non-contact speedometer.

  The expansion / contraction frequency f is the number of expansions / contractions of the casting ribbon for one second. The change in the length of the casting ribbon is continuously measured from the casting video image, and is obtained by performing frequency analysis.

  The expansion / contraction rate e is a value obtained by dividing the difference between the maximum length and the minimum length of the casting ribbon by the average length.

  In order to set the casting speed, stretching frequency and stretching ratio within the predetermined ranges as described above, pulsation of the solution flow rate, mechanical vibration of the casting part, uneven speed of the support, static of the die lip discharge ribbon part This can be achieved by suppressing pressure fluctuation and dynamic pressure fluctuation, setting an appropriate ribbon length, and the like.

  The static pressure fluctuation range of the atmosphere including the casting ribbon is preferably 2.4 Pa or less, more preferably 2.0 Pa or less, and most preferably 0.5 Pa or less. When the suppression pressure fluctuation range exceeds 2.4 Pa, the thickness unevenness becomes too large to be put into practical use. The static pressure fluctuation width can be reduced to 2.4 Pa or less by preventing vibration of the air duct. Static pressure fluctuation range is a method of continuously measuring static pressure with a pressure sensor and reading the periodic static pressure fluctuation period and the maximum and minimum values of static pressure fluctuation from the chart, and frequency analysis of static pressure fluctuation values. And the maximum peak value can be measured by a method of reading.

  An example of a solution casting apparatus for producing a polymer resin film according to the present invention will be described with reference to FIGS.

  FIG. 3 is a schematic diagram of a casting die portion of the solution casting apparatus. In FIG. 3, 1 is a casting die, 2 is a support (casting band or casting drum), 3 is a decompression chamber, and 4 is a casting support from the casting die 1 (casting band or casting drum) 2. This is a casting ribbon cast on

  The solution casting apparatus may be a solution casting apparatus using a casting band whose surface is mirror-finished or a solution casting apparatus using a casting drum. A solution casting apparatus using a casting band is shown in FIG. 4, and a solution casting apparatus using a casting drum is shown in FIG.

  In the band-type solution casting apparatus shown in FIG. 4, reference numeral 10 denotes a casting die, and a rotating drum 20 is provided facing the casting die 10, and a casting band 30 is wound around the rotating drum 20. It is supposed to run. A decompression chamber 40 is provided adjacent to the casting die 10, and the decompression chamber 40 is connected to the blower 70 via a suction duct 50 and a buffer tank 60.

  In the drum type solution casting apparatus shown in FIG. 5, reference numeral 80 denotes a casting drum, which is provided in place of the rotating drum 20 and the casting band 30 in the band type solution casting apparatus. The decompression chamber 40, the suction duct 50, the buffer tank 60, and the blower 70 are configured identically.

  As the casting die, those shown in FIGS. 6, 7 and 8 can be used.

  FIG. 6 shows a casting die used for forming a single-layer film. The casting die 10 has a single manifold 11 formed therein. FIG. 7 shows a multi-manifold type co-casting die. The co-casting die 10 is formed with three manifolds 12 and can form a film having a three-layer structure. FIG. 8 shows a feed block type co-casting die. The co-casting die 10 is provided with a manifold 13 and a feed block 14 which are joined together in the feed block 13 to form a plurality of layers (FIG. 8). In this case, the dope having three layers is cast. In the above casting die, a coat hanger die is used, but the present invention is not limited to this, and a die having another shape such as a T die may be used.

  The die lip clearance c1 in the solution casting method is usually set in the range of 0.2 mm to 3 mm, preferably in the range of 0.5 mm to 2.5 mm, but is not limited thereto.

  The distance h between the casting die and the support is usually set in the range of 1 mm to 10 mm, preferably in the range of 1.5 mm to 6 mm, but is not limited thereto.

  The decompression degree p of the decompression chamber is usually set in the range of −500 to −10 Pa, and preferably set to −400 to −20 Pa, but is not limited thereto.

  The casting speed v is usually set in the range of 3 m / min to 150 m / min, and preferably in the range of 10 m / min to 100 m / min, but is not limited thereto.

  The thickness t of the film is preferably 20 to 500 μm, more preferably 30 to 300 μm, and most preferably 35 to 200 μm, but is not limited thereto.

  The pulsation of the solution flow rate is 0.3% or less, the vibration displacement of the casting die is 0.02% or less of the distance between the die and the support, and the speed variation of the support is 0.02 with respect to the average speed of the support. % Or less is preferable.

  Since the dynamic pressure disturbance acting on the casting ribbon can be reduced in the vicinity of the casting portion of the solution casting apparatus, it is preferable to provide a wind shielding means. As the wind shield means, a wind shield plate, a wind shield block, a wind shield box, and wind shield fins can be used. Moreover, it is preferable to provide a suction means (blower etc.) in the wind-shielding means in order to increase the wind-shielding effect. These wind shielding means and suction means may be used alone or in any combination.

An example of a solution casting apparatus provided with a wind shielding means will be described with reference to FIGS.
The solution casting apparatus shown in FIG. 9 is provided with a wind shielding plate 91 in close contact with the downstream side of the casting die 10 (the direction in which the casting ribbon 100 flows; the same applies hereinafter). The solution casting apparatus shown in FIG. 10 is provided with a wind shielding plate 91 in close contact with the upstream side of the casting die 10 (the direction opposite to the direction in which the casting ribbon flows, the same applies hereinafter). In the solution casting apparatus shown in FIG. 11, a wind shielding plate 91 is provided on the downstream side of the casting die 10 with a small gap. In the solution film-forming apparatus shown in FIG. 12, a wind shielding plate 91 is provided on the upstream side of the casting die 10 with a small gap. In the solution casting apparatus shown in FIG. 13, two wind shielding plates 91 are provided on the downstream side of the casting die 10 with a slight gap therebetween. In the solution casting apparatus shown in FIG. 14, two wind shielding plates 91 are provided on the upstream side of the casting die 10 with a small gap therebetween.

  The solution casting apparatus shown in FIG. 15 is provided with a wind shielding block 92 in close contact with the downstream side of the casting die 10. The solution casting apparatus shown in FIG. 16 is provided with a wind shielding block 92 in close contact with the upstream side of the casting die 10. In the solution casting apparatus shown in FIG. 17, a wind shielding block 92 is provided on the downstream side of the casting die 10 with a small gap. In the solution casting apparatus shown in FIG. 18, wind shielding blocks 92 are provided on the downstream side of the casting die 10 with a small gap therebetween.

  The solution casting apparatus shown in FIG. 19 is provided with a wind shielding box 93 in close contact with the downstream side of the casting die 10. The solution casting apparatus shown in FIG. 20 is provided with a wind shielding box 93 in close contact with the upstream side of the casting die 10. The solution casting apparatus shown in FIG. 21 is provided with a wind shielding box 93 in close contact with the downstream side of the casting die 10, and the wind shielding box 93 is provided with a suction blower 94. The solution casting apparatus shown in FIG. 22 is provided with a wind shield box 93 in close contact with the upstream side of the casting die 10, and the wind shield box 93 is provided with a suction blower 94.

  The solution casting apparatus shown in FIG. 23 is provided with wind shielding fins 95 in close contact with the downstream side of the casting die 10. The solution casting apparatus shown in FIG. 24 is provided with wind shielding fins 95 in close contact with the upstream side of the casting die 10. The solution casting apparatus shown in FIG. 25 is provided with a short wind-shielding fin 95 at a small interval on the downstream side of the casting die 10. In the solution casting apparatus shown in FIG. 26, a short wind-shielding fin 95 is provided upstream of the casting die 10.

  The solution casting apparatus shown in FIG. 27 is provided with wind shielding plates 91 in close contact with both sides of the casting die 10. In the solution casting apparatus shown in FIG. 28, wind shielding plates 91 are provided on both sides of the casting die 10 with a small gap therebetween. The solution casting apparatus shown in FIG. 29 is provided with wind shielding blocks 92 in close contact with both sides of the casting die 10. The solution casting apparatus shown in FIG. 30 is provided with wind shielding boxes 93 in close contact with both sides of the casting die 10. The solution casting apparatus shown in FIG. 31 is provided with wind shielding plates 93 in close contact with both sides of the casting die 10, and the wind shielding box 93 is provided with a blower 94. The solution casting apparatus shown in FIG. 32 is provided with wind shielding fins 95 in close contact with both sides of the casting die 10. The solution casting apparatus shown in FIG. 33 is provided with short wind-shielding fins 95 on both sides of the casting die 10 with a small gap therebetween.

The polymer resin film of the present invention is produced by a solution casting method. Cellulose acylate, polycarbonate, or the like is used as a material polymer of the polymer solution used in this solution casting method. Details of the cellulose acylate are described below. Preferred cellulose acylates are those in which the substitution degree of the hydroxyl group of cellulose satisfies all of the following formulas (1) to (4).
(1) 2.6 ≦ A + B ≦ 3.0
(2) 2.0 ≦ A ≦ 3.0
(3) 0 ≦ B ≦ 0.8
(4) 1.9 <AB

  Here, A and B represent the substituent of the acyl group substituted by the hydroxyl group of cellulose, A is the substitution degree of an acetyl group, and B is the substitution degree of a C3-C5 acyl group. . Cellulose has three hydroxyl groups in one glucose unit, and the above number represents the degree of substitution with respect to the hydroxyl group 3.0, and the maximum degree of substitution is 3.0. Cellulose triacetate generally has a substitution degree of A of 2.6 or more and 3.0 or less (in this case, there is a maximum of 0.4 hydroxyl groups not substituted), and B = 0 is cellulose triacetate. The cellulose acylate used in the polymer solution of the solution film-forming method of the present invention is cellulose triacetate whose acyl groups are all acetyl groups, and an acetyl group of 2.0 or more and an acyl group of 3 to 5 carbon atoms is 0.00. It is preferably 8 or less and an unsubstituted hydroxyl group of 0.4 or less, particularly preferably cellulose triacetate having a substitution degree of 2.6 to 3.0. The degree of substitution can be obtained by calculation by measuring the degree of binding of acetic acid substituted with a hydroxyl group of cellulose and a fatty acid having 3 to 5 carbon atoms. As a measuring method, it can carry out according to ASTM D-817-91.

Other acyl groups having 3 to 5 carbon atoms such as acetyl group are propionyl group (C ₂ H ₅ CO—), butyryl group (C ₃ H ₇ CO—) (n-, iso-), valeryl group (C ₄ H ₉ CO-) (n-, iso-, sec-, tert-), among which n-substituted ones are preferred from the viewpoint of mechanical strength when formed into a film, ease of dissolution, etc., and in particular, n-propionyl Groups are preferred. Moreover, when the substitution degree of an acetyl group is low, mechanical strength and heat-and-moisture resistance deteriorate. When the degree of substitution of the acyl group having 3 to 5 carbon atoms is high, the solubility in an organic solvent is improved. However, if the degree of substitution is within the above range, good physical properties are exhibited.

The degree of polymerization (average viscosity) of cellulose acylate is preferably from 200 to 700, particularly preferably from 250 to 550. The viscosity average degree of polymerization (DP) can be determined with an Ostwald viscometer, and is determined from the measured intrinsic viscosity [η] of cellulose acylate according to the following formula.
DP = [η] / Km (where Km is a constant 6 × 10 ⁻⁴ )

  Examples of cellulose as a cellulose acylate raw material include cotton linter and wood pulp. Any cellulose acylate obtained from any raw material cellulose may be used, or these may be used in combination.

  Examples of organic solvents that dissolve cellulose acylate include hydrocarbons (eg benzene, toluene, cyclopentane, cyclohexane, cycloheptane, cyclooctane), halogenated hydrocarbons (eg methylene chloride, chlorobenzene), alcohols (eg : Methanol, ethanol, diethylene glycol, n-propyl alcohol, isopropyl alcohol, n-butanol, propanol, iso-propanol, 1-butanol, t-butanol, 2-methyl-2-butanol, 2-methoxyethanol, 2-butoxyethanol ), Ketones (eg, acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone, methylcyclohexanone), esters (eg, methyl acetate, ethyl acetate, propyl acetate, ethyl formate, Propyl acid, pentyl formate, butyl acetate, pentyl acetate and 2-ethoxy-ethyl acetate) and ethers (eg tetrahydrofuran, methyl cellosolve, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, Anisole and phenetole).

  A halogenated hydrocarbon having 1 to 7 carbon atoms is preferably used, and methylene chloride is most preferably used. From the viewpoint of physical properties such as solubility of cellulose acylate, peelability from the support, mechanical strength of the film, optical properties, etc., in addition to methylene chloride, one or several alcohols having 1 to 5 carbon atoms are mixed. It is preferable. 2-25 mass% is preferable with respect to the whole solvent, and, as for content of alcohol, 5-20 mass% is more preferable. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, etc., but methanol, ethanol, n-butanol, or a mixture thereof is preferably used.

  The solvent is removed in the formation of the cellulose ester film. The residual amount of solvent is generally less than 5% by weight. The residual amount is preferably less than 1% by mass, and more preferably less than 0.5% by mass.

  The polymer solution used in the polymer resin film solution casting method of the present invention contains various additives (for example, plasticizers, ultraviolet absorbers, deterioration inhibitors, fine particle powders, release agents) according to the use in each preparation step. Molds, optical property modifiers, fluorosurfactants). Further, the addition may be performed at any time in the polymer solution preparation step, but may be performed by adding an additive to the final preparation step of the polymer solution preparation step.

  As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Examples of phosphate esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. Can be given. Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethyl hexyl phthalate (DEHP). Examples of citrate esters include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB), acetyltriethyl citrate, and acetyltributyl citrate.

  Examples of other carboxylic acid esters include trimellitic acid esters such as butyl oleate, methyl acetyl ricinoleate, dibutyl sebacate, and trimethyl trimellitate. Examples of glycolic acid esters include triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, and butyl phthalyl butyl glycolate.

  Among the plasticizers exemplified above, triphenyl phosphate, biphenyl diphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diethyl hexyl phthalate , Triacetin, ethyl phthalyl ethyl glycolate, trimethyl trimellitate and the like are preferably used. In particular, triphenyl phosphate, biphenyl diphenyl phosphate, diethyl phthalate, ethyl phthalyl ethyl glycolate, and trimethyl trimellitate are preferable.

  The above plasticizers may be used alone or in combination of two or more. 0.1-20 mass% is preferable with respect to a cellulose acylate, and, as for the addition amount of a plasticizer, 5-15 mass% is more preferable. When the addition amount is less than 0.1% by mass, the effect of addition cannot be sufficiently exhibited, and when the addition amount exceeds 20% by mass, the film surface may bleed out.

  In addition, in the present invention, (di) pentaerythritol esters described in JP-A No. 11-124445, glycerol esters described in JP-A No. 11-246704, and JP-A No. 2000 are used as plasticizers for reducing the optical anisotropy. Diglycerol esters described in JP-A No.-63560, citric acid esters described in JP-A No. 11-92574, substituted phenyl phosphate esters described in JP-A No. 11-90946 are preferably used.

  The ultraviolet absorber can be selected from any type according to the purpose, and a salicylic acid ester-based, benzophenone-based, benzotriazole-based, benzoate-based, cyanoacrylate-based, nickel complex-based absorber or the like is used. However, benzophenone series, benzotriazole series, and salicylic acid ester series are preferred. Examples of benzophenone ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4-methoxybenzophenone, 2, 2′-di-hydroxy-4,4′-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4- (2-hydroxy-3- And methacryloxy) propoxybenzophenone. As a benzotriazole ultraviolet absorber, 2 (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-butylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5 And chlorobenzotriazole, 2 (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, and the like. Examples of salicylic acid esters include phenyl salicylate, p-octylphenyl salicylate, and p-tert-butylphenyl salicylate. Among these exemplified ultraviolet absorbers, in particular, 2-hydroxy-4-methoxybenzophenone, 2,2′-di-hydroxy-4,4′-methoxybenzophenone, 2 (2′-hydroxy-3′-tert-butyl- 5'-methylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) ) Benzotriazole, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole is particularly preferred.

  As the ultraviolet absorber, it is preferable to use a combination of a plurality of absorbers having different absorption wavelengths because a high blocking effect can be obtained in a wide wavelength range. From the viewpoint of preventing deterioration of the liquid crystal, the ultraviolet absorbent for liquid crystal is preferably excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less, and from the viewpoint of liquid crystal display properties, the absorption of visible light having a wavelength of 400 nm or more is small. Examples include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. Particularly preferred ultraviolet absorbers are benzotriazole compounds and benzophenone compounds. Among these, a benzotriazole-based compound is preferable because unnecessary coloring with respect to the cellulose ester is small.

  As for the UV absorber, JP-A-60-235852, JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, JP-A-6-107854. 118233, 6-148430, 7-11056, 7-11055, 7-11056, 8-29619, 8-239509, JP-A-2000-204173 There is.

  0.001-5 mass% is preferable with respect to a cellulose acylate, and, as for the addition amount of a ultraviolet absorber, 0.01-1 mass% is more preferable. If the addition amount is less than 0.001% by mass, the effect of addition cannot be sufficiently exhibited. If the addition amount exceeds 5% by mass, the ultraviolet absorber may bleed out to the film surface.

  Further, the ultraviolet absorber may be added at the same time as dissolving the cellulose acylate, or may be added to the polymer solution after dissolution. In particular, a mode in which a UV absorber solution is added to a polymer solution immediately before casting using a static mixer or the like is preferable because spectral absorption characteristics can be easily adjusted.

  The deterioration inhibitor can prevent cellulose triacetate and the like from deteriorating and decomposing. Examples of the deterioration preventing agent include butylamine, hindered amine compounds (JP-A-8-325537), guanidine compounds (JP-A-5-271471), benzotriazole-based UV absorbers (JP-A-6-235819), and benzophenone-based compounds. There are compounds such as UV absorbers (JP-A-6-118233).

  Among these, examples of hindered amine compounds include t-butylamine, triphenylamine, and tribenzylamine. Examples of guanidine derivatives include compounds represented by the following formulas (1a) and (1b).

  The addition amount of the deterioration preventing agent is preferably 0.001 to 5%, more preferably 0.01 to 1%. If the addition amount is less than 0.001%, the effect of addition is small, and if the addition amount exceeds 5%, the raw material cost increases, which is disadvantageous.

  As the fine particle powder, silica, kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, alumina and the like can be arbitrarily used depending on the purpose. These fine particle powders are preferably dispersed in the binder solution by any means such as a high-speed mixer, a ball mill, an attritor, or an ultrasonic disperser before being added to the polymer solution. As the binder, cellulose acylate is preferable. It is also preferable to carry out dispersion together with other additives such as ultraviolet absorbers. The dispersion solvent is arbitrary, but a composition close to that of the polymer solution solvent is preferable.

  The number average particle size of the fine particle powder is preferably from 0.01 to 100 μm, particularly preferably from 0.1 to 10 μm. The above dispersion may be added simultaneously to the cellulose acylate dissolving step, or can be added to the polymer solution in any step, but it is preferable to add it just before casting using a static mixer or the like as with the ultraviolet absorber.

  The content of the fine particle powder is preferably 0.001 to 5% by mass, and more preferably 0.01 to 1% by mass with respect to the cellulose acylate. If the addition amount is less than 0.001% by mass, the effect of addition cannot be exhibited sufficiently, and if the addition amount exceeds 5% by mass, the appearance surface may be deteriorated.

  As the mold release agent, a surfactant is effective, and is not particularly limited, such as a phosphoric acid type, a sulfonic acid type, a carboxylic acid type, a nonionic type, and a cationic type. These are described in, for example, JP-A-61-243837. 0.001-2 mass% is preferable with respect to a cellulose acylate, and, as for the addition amount of a mold release agent, 0.01-1 mass% is more preferable. If the addition amount is less than 0.001% by mass, the effect of addition cannot be sufficiently exerted, and if the addition amount exceeds 2% by mass, precipitation or insoluble matter may occur.

  Nonionic surfactants include surfactants having nonionic hydrophilic groups such as polyoxyethylene, polyoxypropylene, polyoxybutylene, polyglycidyl and sorbitan, and specifically include polyoxyethylene alkyl ethers, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl ethers. Oxyethylene alkyl phenyl ether, polyoxyethylene-polyoxypropylene glycol, polyhydric alcohol fatty acid partial ester, polyoxyethylene polyhydric alcohol fatty acid partial ester, polyoxyethylene fatty acid ester, polyglycerin fatty acid ester, fatty acid diethanolamide, triethanolamine Mention may be made of fatty acid partial esters.

  Examples of the anionic surfactant include carboxylate, sulfate, sulfonate, and phosphate ester salt. Representative examples include fatty acid salt, alkylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl sulfonate, α-olefin sulfonate, dialkylsulfosuccinate, α-sulfonated fatty acid salt, N-methyl-N oleyl taurine, petroleum sulfonate, alkyl sulfate, sulfated oil, polyoxyethylene alkyl ether sulfate, poly Examples thereof include oxyethylene alkyl phenyl ether sulfate, polyoxyethylene styrenated phenyl ether sulfate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, and naphthalene sulfonate formaldehyde condensate.

  Examples of the cationic surfactant include amine salts, quaternary ammonium salts, pyridinium salts, and the like. Primary to tertiary fatty amine salts, quaternary ammonium salts (tetraalkyl ammonium salts, trialkylbenzyl ammonium salts, Alkyl pyridium salt, alkyl imidazolium salt, etc.). Examples of amphoteric surfactants include carboxybetaine and sulfobetaine, such as N-trialkyl-N-carboxymethylammonium betaine and N-trialkyl-N-sulfoalkyleneammonium betaine.

  By adding the fluorosurfactant, an antistatic effect can be exhibited. The addition amount of the fluorosurfactant is preferably 0.002 to 2% by mass and more preferably 0.01 to 0.5% by mass with respect to the cellulose acylate. If the addition amount is less than 0.002% by mass, the effect of addition cannot be sufficiently exhibited, and if the addition amount exceeds 2% by mass, precipitation or insoluble matter may occur.

  In the present invention, a retardation increasing agent (optical property adjusting agent) can be added. The optical anisotropy can be controlled by adding a retardation increasing agent. The retardation increasing agent is preferably an aromatic compound having at least two aromatic rings in order to adjust the retardation of the cellulose acylate film. An aromatic compound is used in 0.01-20 mass parts with respect to 100 mass parts of cellulose acylates. The aromatic compound is preferably used in the range of 0.05 to 15 parts by mass, and more preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the cellulose acylate. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring.

  The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring). The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.

  In the present invention, a colorant can be added. By adding a colorant, light piping can be prevented when used for a photosensitive material support. The amount of the colorant added is preferably 10 to 1000 ppm, more preferably 50 to 500 ppm, by weight with respect to cellulose acylate.

  In the polymer solution of the present invention, a heat stabilizer such as a salt of an alkaline earth metal such as lucium and magnesium, an antistatic agent, a flame retardant, a lubricant, an oil agent and the like can be appropriately added as necessary. .

It describes about the optical characteristic of the film manufactured by the solution casting method of this invention. First, the in-plane retardation (Re) of the film will be described. The measurement method uses an ellipsometer (Ellipsometer AEP-100: manufactured by Shimadzu Corporation), and the in-plane longitudinal and lateral directions at a wavelength of 632.8 nm. Is obtained by multiplying the difference in refractive index by the film thickness.
Re = (nx−ny) × d
nx: refractive index in the horizontal direction
ny: longitudinal refractive index

The smaller the retardation (Re) is, the smaller the optical anisotropy in the in-plane direction is, and it is used in the range of 0 to 300 nm depending on the application. The retardation in the thickness direction (Rth) of the film is also important, and is obtained by multiplying the birefringence in the thickness direction at a wavelength of 632.8 nm by the film thickness, and is obtained by the following formula.
Rth = {(nx + ny) / 2−nz} × d
nx: refractive index in the horizontal direction
ny: longitudinal refractive index
nz: refractive index in the thickness direction

  A smaller refractive index in the thickness direction indicates that there is no optical anisotropy in the thickness direction, but a preferable range is determined depending on the intended use. In general, the Rth of the cellulose acylate film produced according to the present invention is 0 nm to 600 nm per 100 μm, and further used at 0 nm to 400 nm.

  The polymer resin film of the present invention can also be used as, for example, a polarizing plate protective film, an optical compensation sheet, an AR film, an LR film, an optical film such as an AG film support film, and a support film for a photographic material. .

  When the polymer resin film of the present invention is used as an optical compensation sheet, the film itself can be used as the optical compensation sheet. When the film itself is used as an optical compensation sheet, it is preferable to arrange the transmission axis of the polarizing plate and the slow axis of the optical compensation sheet so that they are substantially parallel or perpendicular. The arrangement of the polarizing plate and the optical compensation sheet is described in JP-A-10-48420. The liquid crystal display device comprises a liquid crystal cell having a liquid crystal supported between two electrode substrates, two polarizing plates disposed on both sides thereof, and at least one sheet between the liquid crystal cell and the polarizing plate. An optical compensation sheet is arranged.

  The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The liquid crystal cell may further be provided with a gas barrier layer, a hard coat layer, or an undercoat layer (undercoat layer) (used for adhesion of the transparent electrode layer). These layers are usually provided on the substrate. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

  The optical compensation sheet has birefringence and is used for the purpose of removing the color of the display screen of the liquid crystal display device or improving the viewing angle characteristics. The cellulose acylate film itself according to the present invention can be used as an optical compensation sheet. Further, the function may be imparted as an antireflection layer, an antiglare layer, a λ / 4 layer or a biaxially stretched cellulose acylate film. In addition, in order to improve the viewing angle of the liquid crystal display device, the cellulose acylate film of the present technology and a film exhibiting a birefringence opposite to that (a positive / negative relationship) may be used as an optical compensation sheet. .

  In addition, optical compensation sheets in which an optically anisotropic layer containing a liquid crystal compound (particularly a discotic liquid crystal molecule) is provided on a support have been proposed (Japanese Patent Laid-Open Nos. 3-9325 and 6-148429). 8-50206 and 9-26572). The polymer resin film of the present invention can also be used as a support for such an optical compensation sheet.

  Examples of the polarizing element of the polarizing plate include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. Any polarizing element is generally manufactured using a polyvinyl alcohol film. The protective film of the polarizing plate preferably has a thickness of 25 to 350 μm, and more preferably 40 to 200 μm. The liquid crystal display device may be provided with a surface treatment film. The functions of the surface treatment film include hard coat, anti-fogging treatment, anti-glare treatment and anti-reflection treatment.

  The optically anisotropic layer is preferably a layer containing negatively uniaxially tilted and aligned discotic liquid crystal molecules. The layer containing the discotic liquid crystalline molecules may be hybrid-aligned in which the angle formed by the disk surface and the support surface changes in the depth direction of the optically anisotropic layer, and the disk surface is parallel to the support surface. Homeotropic alignment, homogeneous alignment in which the disk surface is perpendicular to the support surface, or twist alignment in which the disk surface is twisted in the depth direction of the optically anisotropic layer may be employed. Moreover, the orientation in which these orientations are mixed (for example, hybrid orientation + twist orientation) may be used. Among these, the hybrid orientation is preferable. The optical axis of each discotic liquid crystalline molecule exists in the normal direction of the disk surface. However, the optical axis does not exist in the entire layer in which the discotic liquid crystalline molecules are hybrid-aligned.

The film produced by the solution casting method of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted
Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroelectric Liquid Crystal), OCB (Optically Compensated Bend) Various display modes such as Aligned Nematic) have been proposed. In addition, a display mode in which the above display mode is oriented and divided has been proposed. The cellulose acylate film is effective in any display mode liquid crystal display device. Further, it is effective in any of a transmissive type, a reflective type, and a transflective liquid crystal display device.

  The polymer resin film of the present invention may be used as a support for an optical compensation sheet of a TN type liquid crystal display device having a TN mode liquid crystal cell. TN mode liquid crystal cells and TN type liquid crystal display devices have been well known for a long time. The optical compensation sheet used for the TN liquid crystal display device is described in JP-A-3-9325, JP-A-6-148429, JP-A-8-50206, and JP-A-9-26572. Moreover, it is described in Mori et al. (Jpn. J. Appl. Phys. Vol. 36 (1997) p. 143 and Jpn. J. Appl. Phys. Vol. 36 (1997) p. 1068). is there. The TN liquid crystal display device is described in JP-A-10-123478, WO98848320, and Japanese Patent No. 3022477.

  The polymer resin film of the present invention may be used as a support for an optical compensation sheet of an STN type liquid crystal display device having an STN mode liquid crystal cell. In general, in a STN type liquid crystal display device, rod-like liquid crystalline molecules in a liquid crystal cell are twisted in the range of 90 to 360 degrees, and the refractive index anisotropy (Δn) and cell gap (d) of the rod-like liquid crystalline molecules. Product (Δnd) is in the range of 300 to 1500 nm. The optical compensation sheet used in the STN type liquid crystal display device is described in JP-A-2000-105316.

  The polymer resin film of the present invention may be used as a support for an optical compensation sheet of a VA liquid crystal display device having a VA mode liquid crystal cell. In the optical compensation sheet used for the VA liquid crystal display device, it is preferable that the direction in which the absolute value of retardation is minimum does not exist in the plane of the optical compensation sheet or in the normal direction. The optical properties of the optical compensation sheet used in the VA liquid crystal display device are determined by the optical properties of the optically anisotropic layer, the optical properties of the support, and the arrangement of the optically anisotropic layer and the support. . When two optical compensation sheets are used in the VA liquid crystal display device, the in-plane retardation of the optical compensation sheet is preferably in the range of −5 nm to 5 nm. Therefore, the absolute value of the in-plane retardation of each of the two optical compensation sheets is preferably 0 to 5. When one optical compensation sheet is used in the VA liquid crystal display device, it is preferable that the in-plane retardation of the optical compensation sheet be in the range of −10 nm to 10 nm.

  The polymer resin film of the present invention may be used as a support for an optical compensation sheet of an OCB type liquid crystal display device having an OCB mode liquid crystal cell or a HAN type liquid crystal display device having a HAN mode liquid crystal cell. In the optical compensation sheet used for the OCB type liquid crystal display device or the HAN type liquid crystal display device, it is preferable that the direction in which the absolute value of retardation is minimum does not exist in the plane of the optical compensation sheet or in the normal direction. The optical properties of the optical compensation sheet used in the OCB type liquid crystal display device or the HAN type liquid crystal display device are also the optical properties of the optically anisotropic layer, the optical properties of the support, and the optically anisotropic layer and the support. Is determined by the arrangement of An optical compensation sheet used for an OCB type liquid crystal display device or a HAN type liquid crystal display device is described in JP-A-9-197397. Moreover, it is described in Mori et al. (Jpn. J. Appl. Phys. Vol. 38 (1999) p. 2837).

  The polymer resin film of the present invention may be used as a support for an optical compensation sheet of an ASM type liquid crystal display device having a liquid crystal cell of ASM (Axial Symmetrical Microcell) mode. The ASM mode liquid crystal cell is characterized in that the thickness of the cell is maintained by a resin spacer whose position can be adjusted. Other properties are the same as those of the TN mode liquid crystal cell. The ASM mode liquid crystal cell and the ASM type liquid crystal display device are described in a paper (Kume et al., SID 98 Digest 1089 (1998)) outside Kume.

The raw materials used in the solution casting process are as follows.
Cellulose triacetate 100 parts by weight Triphenyl phosphate 10 parts by weight Biphenyl diphenyl phosphate 5 parts by weight Methylene chloride 315 parts by weight Methanol 60 parts by weight n-butanol 10 parts by weight Product thickness after drying 40, 80 μm
Decompression chamber decompression degree 0-500Pa

Side stream dope composition during co-casting Cellulose triacetate 100 parts by weight Triphenyl phosphate 10 parts by weight Biphenyl diphenyl phosphate 5 parts by weight Methylene chloride 400 parts by weight Methanol 75 parts by weight n-butanol 13 parts by weight Total product thickness after drying 80 μm
Mainstream thickness 76μm
Side flow thickness (upper and lower layers) 2μm each

  Using the casting apparatus shown in FIG. 3, the average length l of the casting ribbon, the static pressure fluctuation width Δp of the atmosphere including the casting ribbon, the thickness unevenness pitch a, the thickness unevenness rate d, under the conditions of the example, While measuring the expansion / contraction frequency f and the expansion / contraction rate e of the casting ribbon, the coating unevenness of the formed film was evaluated by visual observation.

[Example 1]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = −200 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 0.9mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon l = 10 mm, the static pressure fluctuation width Δp = 0.5 Pa of the atmosphere including the casting ribbon, the thickness variation pitch a = 0.9 cm, and the thickness variation ratio d = 0.3%. The expansion / contraction frequency f = 93 (1 / s), and the expansion / contraction ratio e of the casting ribbon was 0.3%.

  This example entered the region below the curve b in FIG. 1, and entered the region below the curve d in FIG. 2, and no coating unevenness was visible.

[Example 2]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = -100 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 0.9mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon l = 14 mm, the static pressure fluctuation range Δp = 0.4 Pa of the atmosphere including the casting ribbon, the thickness unevenness pitch a = 1.6 cm, the thickness unevenness ratio d =, 0.4. %, Stretching frequency f = 52 (1 / s), stretching ratio e of the casting ribbon was 0.4%.

  This example entered the region below the curve b in FIG. 1, and entered the region below the curve d in FIG. 2, and no coating unevenness was visible.

[Example 3]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = -40 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 0.9mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon l = 19 mm, the static pressure fluctuation width Δp = 0.4 Pa of the atmosphere including the casting ribbon, the thickness unevenness pitch a = 2.4 cm, and the thickness unevenness ratio d = 0.9. %, Stretching frequency f = 34.7 (1 / s), stretching ratio e of the casting ribbon e = 0.9%.

  This example entered the region below the curve b in FIG. 1, and entered the region below the curve d in FIG. 2, and no coating unevenness was visible.

[Example 4]
Film formation was performed under the following conditions.
1) Distance h = 1.5 mm between casting die and support
2) Decompression degree of the decompression chamber p = 0 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 1.2mm
5) Casting speed v = 58.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon l = 12 mm, the static pressure fluctuation width Δp = 0.2 Pa of the atmosphere including the casting ribbon, the thickness variation pitch a = 1.8 cm, the thickness variation ratio d =, 0.7 %, Stretching frequency f = 32.4 (1 / s), stretching ratio e = 0.7% of the casting ribbon.

  This example entered the region between the curve a and the curve b in FIG. 1, and entered the region between the curve c and the curve d in FIG. 2, and although the coating unevenness was visible, it was weak.

[Example 5]
Film formation was performed under the following conditions.
1) Distance h = 5 mm between casting die and support
2) Decompression degree of the decompression chamber p = 10 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 1.5mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon 1 = 26 mm, the static pressure fluctuation width Δp = 2.0 Pa of the atmosphere including the casting ribbon, the thickness variation pitch a = 4.0 cm, and the thickness variation ratio d = 9.0%. The expansion / contraction frequency f = 20.8 (1 / s), and the expansion / contraction ratio e of the casting ribbon was 9.0%.

  This example entered the region between the curve a and the curve b in FIG. 1, and entered the region between the curve c and the curve d in FIG. 2, and although the coating unevenness was visible, it was weak.

[Example 6]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = 300 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 1.0mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon l = 7.0 mm, the static pressure fluctuation width Δp = 2.0 Pa of the atmosphere including the casting ribbon, the thickness unevenness pitch a = 0.7 cm, and the thickness unevenness ratio d = 0. At 5%, the expansion / contraction frequency f = 119 (1 / s), and the expansion ratio e of the casting ribbon was 0.5%.

  This example entered the region between the curve a and the curve b in FIG. 1, and entered the region between the curve c and the curve d in FIG. 2, and although the coating unevenness was visible, it was weak.

[Example 7]
Film formation was performed under the following conditions.
1) Distance h = 1.5 mm between casting die and support
2) Decompression degree of the decompression chamber p = 0 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 1.2mm
5) Casting speed v = 33.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon 1 = 12.0 mm, the static pressure fluctuation frequency near the ribbon = 170 Hz, the static pressure fluctuation width Δp = 5.0 Pa of the atmosphere including the casting ribbon, and the thickness unevenness pitch a = 0. 0.2 cm, thickness unevenness ratio d = 0.4%, stretching frequency f = 166.5 (1 / s), casting ribbon stretching ratio e = 0.4%.

  This example entered the region between the curve a and the curve b in FIG. 1, and entered the region between the curve c and the curve d in FIG. 2, and although the coating unevenness was visible, it was weak.

[Example 8]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = −300 Pa
3) Mainstream dope viscosity μ = 45 Pa · s
Side flow dope viscosity μs = 20 Pa · s
4) Die lip clearance c1 = 1.0mm
5) Casting speed v = 133.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon 1 = 8 mm, the static pressure fluctuation width Δp = 0.2 Pa of the atmosphere including the casting ribbon, the thickness variation pitch a = 1.2 cm, and the thickness variation ratio d = 0.1%. The expansion / contraction frequency f = 111 (1 / s), and the expansion / contraction ratio e of the casting ribbon was 0.1%.

  This example entered the region below the curve b in FIG. 1, and entered the region below the curve d in FIG. 2, and no coating unevenness was visible.

[Example 9]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = −200 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 0.9mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon 1 = 10 mm, the static pressure fluctuation range Δp = 1.2 Pa of the atmosphere including the casting ribbon, the thickness variation pitch a = 0.9 cm, and the thickness variation ratio d = 0.7%. The expansion / contraction frequency f = 92.6 (1 / s), and the expansion / contraction rate e of the casting ribbon was 0.7%.

  This example entered the region below the curve b in FIG. 1, and entered the region below the curve d in FIG. 2, and no coating unevenness was visible.

[Comparative Example 1]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = -100 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 0.9mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon 1 = 14 mm, the static pressure fluctuation width Δp = 2.4 Pa of the atmosphere including the casting ribbon, the thickness variation pitch a = 1.6 cm, and the thickness variation ratio d = 2.4%. The stretching frequency f was 52 (1 / s), and the stretching ratio e of the casting ribbon was 2.4%.

  This comparative example entered the region above the curve b in FIG. 1, and entered the region above the curve d in FIG. 2, and the coating unevenness looked strong.

[Comparative Example 2]
Film formation was performed under the following conditions.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = -40 Pa
3) Dope viscosity μ = 45 Pa · s
4) Die lip clearance c1 = 0.9mm
5) Casting speed v = 83.3 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon 1 = 19 mm, the static pressure fluctuation width Δp = 2.4 Pa of the atmosphere including the casting ribbon, the thickness unevenness pitch a = 2.4 cm, and the thickness unevenness rate d = 5.3%. The stretching frequency f was 34.7 (1 / s), and the stretching ratio e of the casting ribbon was e = 5.3%.

  This comparative example entered the region above the curve b in FIG. 1, and entered the region above the curve d in FIG. 2, and the coating unevenness looked strong.

[Example 10]
Film formation was performed under the following conditions by changing the dope formulation.
Cellulose triacetate 100 parts by weight Triphenyl phosphate 10 parts by weight Biphenyl diphenyl phosphate 5 parts by weight Methyl acetate 315 parts by weight Ethanol 60 parts by weight n-butanol 10 parts by weight

Cellulose triacetate was swollen with a solvent for 30 minutes, cooled at -70 ° C, and heated to 50 ° C and dissolved.
1) Distance between casting die and support h = 3.5 mm
2) Decompression degree of the decompression chamber p = 0 Pa
3) Dope viscosity μ = 30 Pa · s
4) Die lip clearance c1 = 1.2mm
5) Casting speed v = 16.7 cm / s
6) Base thickness t = 80 μm

  At this time, the average length l of the casting ribbon l = 10 mm, the static pressure fluctuation range Δp = 0.5 Pa of the atmosphere including the casting ribbon, the thickness variation pitch a = 1.0 cm, and the thickness variation ratio d = 0.1%. The expansion / contraction frequency f = 16.7 (1 / s), and the expansion / contraction rate e of the casting ribbon was 0.1%.

  This example entered the region below the curve b in FIG. 1, and entered the region below the curve d in FIG. 2, and no coating unevenness was visible.

[Example 11]
<Preparation of cellulose triacetate solution>
Cellulose triacetate powder (average size: 2 mm) was gradually added to a stainless steel dissolution tank having stirring blades while stirring well in the following solvent mixed solution. After the addition, the mixture was allowed to stand at room temperature (25 ° C.) for 3 hours at 25 ° C. to swell the cellulose triacetate. In addition, methyl acetate, cyclopentanone, acetone, methanol, and ethanol, which are solvents, all have a water content of 0.2% by mass or less.

16 parts by mass of cellulose triacetate (degree of substitution 2.83, viscosity average degree of polymerization 320, water content 0.4% by mass, viscosity of 6% by mass in methylene chloride solution 305 mPa · s)
Methyl acetate 53 parts by weight Cyclopentane 10 parts by weight Acetone 5 parts by weight Methanol 5 parts by weight Ethanol 5 parts by weight Plasticizer A (dipentaerythritol hexaacetate) 3 parts by weight Plasticizer B (triphenyl phosphate) 3 parts by weight Fine particle powder (Silica (particle diameter 20 nm)) 0.1 part by mass UV absorber a 0.1 part by mass (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert- Butylanilino) -1,3,5-triazine)
UV absorber b 0.1 parts by mass (2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole)
UV absorber c 0.1 parts by mass (2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole C ₁₂ H ₂₅ OCH ₂ CH ₂ O—P (═O )-(OK) ₂
0.05 parts by mass

  The viscosity of this solution obtained by the cooling dissolution method described later was 160 Pa · S (45 ° C.).

<Cooling dissolution of cellulose triacetate solution>
The cellulose triacetate solution described above was fed by a screw extruder and passed through the cooling part at −70 ° C. for 3 minutes. Cooling was performed using a refrigerant at −80 ° C. (3M, “Fluorinert”) cooled by a refrigerator. The solution obtained by cooling is heated to 120 ° C. by a heat exchanger provided with a static mixer, held for 3 minutes, cooled, transferred to a stainless steel container at 50 ° C., and heated at 50 ° C. The mixture was stirred for 2 hours for defoaming. The cellulose triacetate solution thus prepared was filtered with a filter paper having an absolute filtration accuracy of 0.01 mm (manufactured by Toyo Filter Paper Co., Ltd., “# 63”), and further, a filter paper having an absolute filtration accuracy of 0.0025 mm (manufactured by Pall, (FH 025)).

<Casting of cellulose triacetate solution by casting>
The cellulose triacetate solution prepared by the above method was 25 Pa · s. This solution was cast under the same conditions as in Example 10 to obtain a cellulose triacetate film.

  As a result, the average length of the casting ribbon is l = 9.5 mm, the static pressure fluctuation range ΔP = 0.5 Pa of the atmosphere including the casting ribbon, the thickness unevenness pitch a = 1.1 mm, and the thickness unevenness rate d = 0. 0.1%, stretching frequency 17.5 (1 / s), stretching rate e of the casting ribbon e = 0.1%.

  This example entered the region below the curve b in FIG. 1, and entered the region below the curve d in FIG. 2, and no coating unevenness was visible.

<Antireflection film>
Using the cellulose triacetate film produced under the above conditions, an antireflection film by coating was produced by the following procedure.

(Preparation of coating solution A for antiglare layer)
125 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (Nippon Kayaku Co., Ltd., “DPHA”), bis (4-methacryloylthiophenyl) sulfide (Sumitomo Seika Co., Ltd., “MPSMA”) ) 125 g was dissolved in 439 g of methyl ethyl ketone / cyclohexanone = 50/50 mass% mixed solvent. Into the obtained solution, 5.0 g of a photopolymerization initiator (Ciba Geigy, “Irgacure 907”) and 3.0 g of photosensitizer (Nippon Kayaku Co., Ltd., “Kayacure DETX”) were added to 49 g of methyl ethyl ketone. The dissolved solution was added. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.60.

  Further, 10 g of a crosslinked polystyrene particle having an average particle diameter of 2 μm (trade name “SX-200H”, manufactured by Soken Chemical Co., Ltd.) was added to this solution, and the mixture was stirred and dispersed at 5000 rpm for 1 hour with a high-speed dispaper. An antiglare layer coating solution was prepared by filtration through a 30 μm polypropylene filter.

(Preparation of coating liquid D for hard coat layer)
A solution obtained by dissolving 250 g of an ultraviolet curable hard coat composition (JSR Corporation, 72% by mass of “Desolite KZ-7689”) in 62 g of methyl ethyl ketone and 88 g of cyclohexanone was added. The refractive index of the coating film obtained by applying this solution and curing with ultraviolet rays was 1.53.

  Further, this solution was filtered through a polypropylene filter having a pore size of 30 μm to prepare a coating solution for a hard coat layer.

(Preparation of coating liquid E for low refractive index layer)
Thermally crosslinkable fluorine-containing polymer having a refractive index of 1.42 (manufactured by JSR Co., Ltd., “TN-049”) 200 93 g of MEK-ST (average particle size of 10 to 20 nm, solid content concentration of 30% by mass of SiO ₂ sol) 8 g of MEK dispersion (manufactured by Nissan Chemical Industries, Ltd.) and 100 g of methyl ethyl ketone were added, and after stirring, the mixture was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution for a low refractive index layer.

The above-mentioned coating liquid D for hard coat layer is applied to the cellulose triacetate film having a thickness of 80 μm using a bar coater, dried at 120 ° C., and then air-cooled metal halide lamp (Igraphics Co., Ltd.) of 160 W / cm. The coating layer was cured by irradiating ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 300 mJ / cm ² to form a hard coat layer having a thickness of 2.5 μm.

  On top of that, the antiglare layer coating solution A was applied using a bar coater, dried and UV cured under the same conditions as the hard coat layer to form an antiglare layer having a thickness of about 1.5 μm. . Further, the coating liquid E for the low refractive index layer is applied thereon using a bar coater, dried at 80 ° C., and further thermally crosslinked at 120 ° C. for 10 minutes to have a low refractive index of 0.096 μm in thickness. A layer was formed.

[Comparative Example 3]
The same cellulose triacetate solution as in Example 11 was used and cast under the same casting conditions as in Comparative Example 1.

  As a result, the average length of the casting ribbon is 1 = 14.5 mm, the static pressure fluctuation range ΔP = 2.5 Pa of the atmosphere including the casting ribbon, the thickness unevenness pitch a = 16 mm, and the thickness unevenness ratio d = 2.5. %, Stretching frequency 53 (1 / s), stretching ratio e = 2.5% of the casting ribbon.

This comparative example entered the region above the curve b in FIG. 1, and entered the region above the curve d in FIG. 2, and the coating unevenness looked strong.
In addition, an antireflection film was produced in the same manner as in Example 11.

[Evaluation of antireflection film]
The antireflection film using the cellulose triacetate film obtained in Example 11 and Comparative Example 3 was evaluated for the following items.

(1) Specular reflectance and tint A spectrophotometer V-550 (manufactured by JASCO Corporation) is equipped with an adapter ARV-474, and an emission angle of -5 at an incident angle of 5 ° in a wavelength region of 380 to 780 nm. The specular reflectivity was measured, and an average reflectivity of 450 to 650 nm was calculated. The antireflection property was evaluated based on the reflectance.
Further, CIE 1976 L * a * b * color space L * value, a * value, and b * value representing the color of the specularly reflected light with respect to the 5 degree incident light of the CIE standard light source D65 are calculated from the measured reflection spectrum. The color of reflected light was evaluated.

(2) Integral reflectance The spectrophotometer V-550 (manufactured by JASCO Corporation) is fitted with an adapter ILV-471, and the integral reflectance at an incident angle of 5 ° is measured in the wavelength region of 380 to 780 nm. An average reflectance of 450 to 650 nm was calculated. The antireflection property was evaluated based on the reflectance.

(3) Haze A haze meter was measured using MODEL 1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.).

(4) Pencil hardness evaluation Pencil hardness evaluation described in JIS K 5400 was performed as an index of scratch resistance. The antireflection film was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and then evaluated using the 3H test pencil specified in JIS S 6006 (load: 1 kg) according to the following criteria.
No scratches are observed in the evaluation of n = 5: ○
In evaluation of n = 5, 1 or 2 scratches:
In evaluation of n = 5, 3 or more scratches: ×

(5) Contact angle After conditioning for 2 hours at a temperature of 25 ° C. and a humidity of 60% RH, the contact angle against water was measured and used as an index of fingerprint adhesion. This fingerprint adhesion is used as an index of surface contamination resistance.

(6) Dynamic friction coefficient The dynamic friction coefficient was used as an index of surface slipperiness. As the dynamic friction coefficient, the value measured at 5 mmφ stainless steel ball, load 100 g, speed 60 cm / min by HEIDON-14 dynamic friction measuring machine after conditioning the antireflection film at 25 ° C. and relative humidity 60% for 2 hours is used. It was.

(7) Evaluation of antiglare property An exposed fluorescent lamp (8000 cd / m ² ) without a louver was projected on the antireflection film, and the degree of blur of the reflected image was evaluated according to the following criteria.
I do not know the outline of the fluorescent lamp at all: ◎
Slightly understand the outline of the fluorescent lamp: ○
The fluorescent light is blurred, but the outline can be identified:
Fluorescent lamp is hardly blurred: ×

(8) Planar evaluation The surface was visually observed and evaluated by the presence or absence of coating unevenness. The evaluation criteria are as follows.
Reflected image looks uniform: ◎
Reflected image looks like stepped unevenness: ×
The above evaluation results are shown in Table 1.

  As a result of the above, both Example 11 and Comparative Example 3 are excellent in antiglare property and antireflection property and weak in color, and reflect film properties such as pencil hardness, fingerprint adhesion (contact angle), and dynamic friction coefficient. The evaluation results were also good.

  However, in Comparative Example 3, the stepwise coating unevenness was visually confirmed, and it was a level that could not be used as an antireflection film.

[Anti-glare anti-reflection polarizing plate]
Using the cellulose triacetate film of Example 11, an antiglare antireflection polarizing plate was prepared. Using this polarizing plate, a liquid crystal display device in which an antireflection film was arranged on the outermost layer was produced. As a result, there was no reflection of external light, and an excellent contrast was obtained. Visibility was good and fingerprinting was good.

  The polarizing plate is made by adsorbing iodine to a stretched polyvinyl alcohol film to produce a polarizing element, and using a polyvinyl alcohol-based adhesive, the anti-reflection film has a slow axis parallel to the transmission axis of the polarizing film. In addition to being attached to one side, a polyvinyl alcohol-based adhesive was used to attach to the opposite side of the polarizing element.

It is a figure showing the relationship between the thickness nonuniformity rate and the thickness nonuniformity pitch, and the visual recognition rate of coating nonuniformity. It is a figure showing the relationship between the casting speed, the expansion-contraction frequency, and the expansion-contraction rate, and the visual recognition rate of coating nonuniformity. It is a schematic diagram of the casting die part of the solution casting apparatus which can be used for the manufacturing method of the polymer resin film by this invention. It is a schematic diagram of the solution casting apparatus which can be used for the manufacturing method of the polymer resin film by this invention. It is a schematic diagram of the solution casting apparatus which can be used for the manufacturing method of the polymer resin film by this invention. It is a schematic cross section of the casting die which can be used for the manufacturing method of the polymer resin film by this invention. It is a schematic cross section of the casting die which can be used for the manufacturing method of the polymer resin film by this invention. It is a schematic cross section of the casting die which can be used for the manufacturing method of the polymer resin film by this invention. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding block. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding block. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding block. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding block. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windbreak box. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windbreak box. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windbreak box. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windbreak box. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding fin. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding fin. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding fin. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding fin. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windshield. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding block. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windbreak box. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the windbreak box. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding fin. It is a schematic diagram of the casting die part of the solution film-forming apparatus provided with the wind-shielding fin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Casting die 2 ... Support body 3 ... Decompression chamber 4 ... Ribbon 10 ... Casting die 20 ... Rotary drum 30 ... Casting band 40 ... Decompression chamber 50 ... Suction duct 60 ... Buffer tank 70 ... Blower 80 ... Casting drum 91 ... Wind shield plate 92 ... Wind shield block 93 ... Wind shield box 94 ... Blower
95 ... Wind shield fins

Claims (6)

A support in which a solution of a polymer resin dissolved in an organic solvent is cast, a casting die for casting the solution on the support, and a casting die in close contact with the casting die on the downstream side or upstream side of the casting die. And a wind shielding block provided. A support in which a solution in which a polymer resin is dissolved in an organic solvent is cast, a casting die for casting the solution on the support, and a casting die on the downstream side of the casting die are provided in close contact with the casting die. A solution casting apparatus comprising: a windshield box; and a blower provided in the windshield box. The solution casting apparatus according to claim 1 or 2, wherein a die lip clearance of the casting die is in a range of 0.2 to 3 mm. The solution casting apparatus according to claim 3, wherein a die lip clearance of the casting die is in a range of 0.5 to 2.5 mm. The solution casting apparatus according to claim 1, 2, 3, or 4, wherein a distance between the support and the casting die is in a range of 1 to 10 mm. 6. The solution casting apparatus according to claim 5, wherein a distance between the support and the casting die is in a range of 1.5 to 6 mm.

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